In Saudi Arabia, dozens of ministers, royals, officials and senior military officers have been dismissed or arrested as part of a new anti-corruption committee.

So how has this happened, and why?

What's actually happened?

Saudi Arabia's leadership has arrested 11 senior princes, four current ministers and tens of former ministers.

It includes businessman Prince Alwaleed bin Talal — whose net worth has been estimated at $22 billion — and is known as the face of business in Saudi Arabia.

He's also the owner of London's famous Savoy hotel.

His firm, Kingdom Holding, is invested in companies like Apple, Twitter and Citigroup.

The BBC is also reporting that the brother of Osama bin Laden — Bakr bin Laden, who runs the Saudi Binladin construction group — was also detained.

The move has been described as a "corruption purge".

But it's not clear what the detainees are suspected of.

State-run media have reported the committee is looking into the deadly floods that overwhelmed the city of Jeddah in 2009 and the Government's response to Middle East Respiratory Syndrome (MERS) virus, which has killed hundreds of people in the past few years.

It's also been reported that they are being detained at the Ritz-Carlton hotel in the diplomatic quarter of the capital city, Riyadh.

How does succession work in the oil-rich nation?

For decades, power has been passed from brother to brother, but that's about to change, with Prince Mohammed set to inherit the throne from his father.

The prince is already defence minister — the youngest in the world — and currently oversees the country's economy, planning, reforms and security.

Previously, King Salman removed his half-brother Prince Muqrin from the line of succession.

By April 2015, Salman had appointed Prince Mohammed bin Salman as second-in-line to the throne, giving him the title of deputy Crown Prince, before making him next in line to the throne in June this year.

In theory, the selection of a Crown Prince once a new king ascends to the throne has been the duty of the "Allegiance Council," a body formed in 2007 by the late King Abdullah and made up of the sons and prominent grandsons of the founding King Abdulaziz.

However, its role, and how much say it's had in the flurry of changes since 2015, has been limited.

How much power does the king have in Saudi Arabia?

Quite a lot.

Despite some efforts at consensus, Saudi Arabia remains an absolute monarchy, and all major decision making still rests with the king.

But even if there's disagreement, the royal family has long followed a tradition of speaking with one voice, particularly on issues of succession, in order to appear united in front of Saudi Arabia's powerful tribes and clergy.

And the arrests of prominent princes appears to have upended the ways in which the royal family handles internal disputes.

It also puts the spotlight on the Crown Prince who hopes to modernise the conservative kingdom that is home to Islam's holiest shrines — Masjid al-Haram, in Mecca, the destination of the Hajj pilgrimage and Medina's Masjid an-Nabawi, which is the burial site of the prophet Mohammad.